It is a card reader alone, which supports upto 4 GB SD/MMC card. "IF" inserted a SD/MMC card, it turns into your normal flash thumb/pen/key drive. It can be the fastest and easiest way to move a large amount of data. USB 2.0 certified for fast data transfer (also backward compatible with USB 1.1). Store all your data, pictures, music and more on this pocket-sized device and then easily transfer files between your laptop and desktop.